1. Field of the Invention
This invention relates to a pen-shaped tire pressure gauge, particularly to one having its pressure measuring head reinforced to prevent it from worn off and prolong its service life.
2. Description of the Prior Art
Most conventional pen-shaped tire pressure gauges are pen-shaped and respectively provided with a pen clip, easy to be carried and having beautiful appearance; therefore they are widely used in related business.
However, the pressure measuring head of the conventional pen-shaped tire pressure gauge is likely to become worn off and the scale rod inside may be pressed to bounce out by inner air pressure after used for a period of time. This is because the body and the interior components of a conventional pen-shaped tire pressure gauge are injection molded of plastic for the purpose of lowering producing cost and facilitating a producing process. Therefore, the plastic pressure measuring head of the conventional tire pressure gauge will become worn off after long-term and continuous contact and pressing against the metallic tube valves of tires for measuring, most likely to render the pressure measuring head cracked and damaged. In addition, during pressure measuring, the scale rod inside the gauge body is pressed by inner high pressure to move outward to indicate the tire pressure thereon. Under the circumstances, the portion around the open end of the tire pressure gauge is inevitable to be frequently bumped by the scale rod and become damaged, rendering the scale rod easy to bounce outward and become damaged. Therefore, it is of great importance to strengthen the pressure measuring head and stabilize the portion around the open end of a pen-shaped tire pressure gauge.